6.12 三列布局<div class="left">左侧定宽</div> <div class="right">右侧定

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .left,.right{
            width: 300px;
            height: 300px;
            background-color: red;
        }
        .left{
            float: left;
        }
        .right{
            float: right;
        }
        .center{
            height: 600px;
            background-color: blue;
            /* 开启bfc */
            overflow: hidden;
        }
    </style>
</head>
<body>
    <div class="left">左侧定宽</div>
    <div class="right">右侧定宽</div>
    <div class="center">中间自适应</div>
</body>
</html>